* {
    margin: 0px;
    padding: 0px;
}

body {
    font-family: '微软雅黑';
}

.operate {
    margin-top: 30px;
}

.stu-message {
    margin-top: 20px;
}

.modal-body input {
    width: 250px;
    text-align: center;
    display: block;
    margin: 0px auto;
    padding: 5px 10px 5px 10px;
    font-size: 18px;
}

.insert-message input {
    margin-top: 10px;
}

.insert-message input:focus {
    width: 280px;
    font-size: 20px;
}

.select {
    float: right;
    margin-right: 100px;
    width: 400px;
}

.tip {
    color: red;
}

.assignment {
    display: none;
}